Debiting 3 years after end of contact + inflated!

Once again my money is being ****** by a corporate giant! I took out a ONE year data contract about 4 years ago (no phones or ****les) with Cell C of 1Gig of data per month for use with my Ipad. I had a big fight with customer services as I discovered shortly after taking out the contract that I would not be allowed to top up the data if the 1Gig was used up. I told them I wanted the contract cancelled as I was not told this - in fact, the person who talked me into the contract told me I would NEVER run out of data agin! So I switched back over to a prepaid Vodacom card which suited me much better as I could add data at will. Now - almost three years later I am still being debited - and now for an amount of R279.00 per month!!!!! I just spoke to customer services and after being transferred to 3 different consultants have been told to cancel a contract that I DO NOT HAVE! They also had the cheek to tell me that I am still liable for another payment in August!! I want my money back!!